Valence Electrons

What are Valence Electrons? The valence electrons are the electrons in the last shell or energy level of an atom. The valence electrons increase in number as you go across a period. When you start the new period, the number drops back down to one and starts increasing again

Energy Level Model Assumes electrons can orbit the nucleus ONLY at certain fixed distances from the nucleus (known as energy levels) Electrons close to the nucleus has LESS energy than one is further When electrons receive energy, they are in an EXCITED state. They can “jump” further away from the nucleus When they lose/give off energy, they return back to their original energy level or GROUND STATE When electrons return to their ground state, they give off the energy in the form of light Electrons can jump any number of energy levels, BUT can’t get stuck in between

Energy Levels There are a maximum number of electrons that can occupy each energy level. Energy Level Max # Electrons 1 2 8 3 18 4 32 8 10 Subdivides into sub levels

Electron Jumping When electrons jump, the number of orbitals that are jumped determines the color of light which is emitted. A longer jump has a shorter wavelength and will produced violet A shorter jump had a longer wavelength and will produce red

Flame Tests Flame tests are used to identify the presence of a relatively small number of metal ions in a compound Different metals will emit different colors when their electrons are excited